Display device

ABSTRACT

A display device includes a scan line extending in a first direction, a data line and a driving voltage line extending in a second direction crossing the first direction, a switching thin film transistor (“TFT”) connected to the scan line and the data line, a driving TFT connected to the switching TFT and including a driving semiconductor layer and a driving gate electrode, a storage capacitor connected to the driving TFT and including first and second storage capacitor plates, a node connection line between the data line and the driving voltage line and connected to the driving gate electrode, and a shielding portion between the data line and the node connection line.

This application claims priority to Korean Patent Application No.10-2016-0074732, filed on Jun. 15, 2016, and all the benefits accruingtherefrom under 35 U.S.C. §119, the content of which in its entirety isherein incorporated by reference.

BACKGROUND 1. Field

One or more exemplary embodiments relate to a display device.

2. Description of the Related Art

Generally, a display device includes a display element and electronicelements for controlling an electrical signal to be applied to thedisplay element. The electronic elements include a thin film transistor(“TFT”), a storage capacitor, and a plurality of wirings.

To accurately control an emission and an emission degree of a displayelement, a number of TFTs electrically connected to one display elementhas increased and a number of the plurality of wirings transferring anelectrical signal to the TFTs has also increased.

SUMMARY

According to a display device of the related art, as intervals betweenelements of a thin film transistor (“TFT”) and/or wirings of a displaydevice are reduced so as to implement a miniaturized or high resolutiondisplay device, disadvantages such as parasitic capacitance of a drivingTFT have increased.

One or more exemplary embodiments include a display device whichprevents occurrence of parasitic capacitance and reduces occurrence ofan off-current. However, the above embodiment is merely provided as anexample, and the scope of the invention is not limited thereto.

Additional exemplary embodiments will be set forth in part in thedescription which follows and, in part, will be apparent from thedescription, or may be learned by practice of the presented exemplaryembodiments.

According to one or more exemplary embodiments, a display deviceincludes a first scan line extending in a first direction, a data lineand a driving voltage line each extending in a second direction crossingthe first direction, a switching TFT connected to the first scan lineand the data line, a driving TFT connected to the switching TFT andincluding a driving semiconductor layer and a driving gate electrode, astorage capacitor connected to the driving TFT and including first andsecond storage capacitor plates, a node connection line connected to thedriving gate electrode and arranged between the data line and thedriving voltage line, and a shielding portion arranged between the dataline and the node connection line.

In an exemplary embodiment, the display device may further include acompensation TFT including a compensation semiconductor layer and acompensation gate electrode, where the compensation TFT turns on inresponse to a scan signal of the first scan line and diode-connects thedriving TFT.

In an exemplary embodiment, one side of the node connection line may beconnected to the compensation semiconductor layer.

In an exemplary embodiment, the driving voltage line may cover at leasta portion of the compensation TFT.

In an exemplary embodiment, the shielding portion may extend in thesecond direction.

In an exemplary embodiment, the display device may further include aninitialization voltage line providing an initialization voltage, and theshielding portion may be electrically connected to the initializationvoltage line.

In an exemplary embodiment, the shielding portion may include at leastone of a shielding semiconductor layer including a same material as thatof the driving semiconductor layer, and a metallic shielding layerincluding a metallic material.

In an exemplary embodiment, the display device may further include asecond scan line extending in the first direction and crossing theshielding portion.

In an exemplary embodiment, the shielding semiconductor layer mayinclude a first shielding region and a second shielding region spacedapart from each other in the second direction with the second scan linetherebetween.

In an exemplary embodiment, the first shielding region may beelectrically connected to the second shielding region by a conductivelayer.

In an exemplary embodiment, the conductive layer may be the metallicshielding layer.

In an exemplary embodiment, the shielding semiconductor layer mayinclude polycrystalline silicon.

In an exemplary embodiment, the metallic shielding layer may include asame material as that of at least one of the data line, the nodeconnection line, and the second storage capacitor plate.

In an exemplary embodiment, the driving gate electrode and the firststorage capacitor plate may include a same material.

In an exemplary embodiment, the display device may further include anorganic light-emitting diode electrically connected to the driving TFT.

A display device according to exemplary embodiments may preventoccurrence of parasitic capacitance and provide a high quality image byreducing an off-current. The scope of the invention is not limited bythis effect.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other exemplary embodiments will become apparent and morereadily appreciated from the following description of the exemplaryembodiments, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a plan view of an exemplary embodiment of a display device;

FIG. 2 is an equivalent circuit diagram of an exemplary embodiment ofone pixel of the display device of FIG. 1;

FIG. 3 is a plan view of the locations of a plurality of thin filmtransistors (“TFTs”), a storage capacitor, and a pixel electrode of thepixel in FIG. 2;

FIGS. 4 to 8 are plan views illustrating elements such as the pluralityof TFTs, the storage capacitor, and the pixel electrode of FIG. 3 on alayer basis;

FIG. 9 is a cross-sectional view of the plurality of TFTs, the storagecapacitor, and the pixel electrode taken along line IX-IX of FIG. 3; and

FIGS. 10 to 14 are plan views of another exemplary embodiment of astructure of a pixel.

DETAILED DESCRIPTION

As the disclosure allows for various changes and numerous exemplaryembodiments, exemplary embodiments will be illustrated in the drawingsand described in detail in the written description. An effect and acharacteristic of the disclosure, and a method of accomplishing thesewill be apparent when referring to exemplary embodiments described withreference to the drawings. This disclosure may, however, be embodied inmany different forms and should not be construed as limited to theexemplary embodiments set forth herein.

Hereinafter, the disclosure will be described more fully with referenceto the accompanying drawings, in which exemplary embodiments of thedisclosure are shown. When description is made with reference to thedrawings, like reference numerals in the drawings denote like orcorresponding elements, and repeated description thereof will beomitted.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items.

Expressions such as “at least one of” when preceding a list of elements,modify the entire list of elements and do not modify the individualelements of the list.

It will be understood that although the terms “first”, “second”, etc.may be used herein to describe various components, these componentsshould not be limited by these terms. These components are only used todistinguish one component from another.

As used herein, the singular forms “a”, “an”, and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise.

It will be further understood that the terms “comprises” and/or“comprising” used herein specify the presence of stated features orcomponents, but do not preclude the presence or addition of one or moreother features or components.

Sizes of elements in the drawings may be exaggerated for convenience ofexplanation. In other words, since sizes and thicknesses of componentsin the drawings are arbitrarily illustrated for convenience ofexplanation, the following exemplary embodiments are not limitedthereto.

When a certain exemplary embodiment may be implemented differently, aspecific process order may be performed differently from the describedorder. For example, two consecutively described processes may beperformed substantially at the same time or performed in an orderopposite to the described order.

It will be understood that when a layer, region, or component isreferred to as being “connected” to another layer, region, or component,it may be “directly connected” to the other layer, region, or componentor may be “indirectly connected” to the other layer, region, orcomponent with other layer, region, or component interposedtherebetween. For example, it will be understood that when a layer,region, or component is referred to as being “electrically connected” toanother layer, region, or component, it may be “directly electricallyconnected” to the other layer, region, or component or may be“indirectly electrically connected” to other layer, region, or componentwith other layer, region, or component interposed therebetween.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and theinvention, and will not be interpreted in an idealized or overly formalsense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. In an exemplary embodiment, a region illustrated ordescribed as flat may, typically, have rough and/or nonlinear features.Moreover, sharp angles that are illustrated may be rounded. Thus, theregions illustrated in the figures are schematic in nature and theirshapes are not intended to FIG. 1 is a plan view of a display deviceaccording to an exemplary embodiment.

Referring to FIG. 1, the display device includes a substrate 110. Thesubstrate 110 includes a display area DA displaying an image and aperipheral area PA around the display area DA. The peripheral area PAdoes not display an image, and thus the peripheral area PA maycorrespond to a dead area.

Pixels PX having various display elements such as organic light-emittingdiodes (“OLEDs”) may be in the display area DA of the substrate 110.Various wirings transferring electrical signals to be applied to thedisplay area DA may be in the peripheral area PA of the substrate 110.Hereinafter, for convenience of description, a display device having anOLED as a display element is described. However, the invention is notlimited thereto.

FIG. 2 is an equivalent circuit diagram of one pixel PX of the displaydevice of FIG. 1, according to an exemplary embodiment.

Referring to FIG. 2, a pixel PX includes signal lines 121, 122, 123,124, and 171, a plurality of thin film transistors (“TFTs”) T1, T2, T3,T4, T5, T6, and T7 connected to the signal lines, a storage capacitorCst, an initialization voltage line 134, a driving voltage line 172, andan OLED.

Although FIG. 2 illustrates that each pixel includes the signal lines121, 122, 123, 124, and 171, the initialization voltage line 134, andthe driving voltage line 172, the invention is not limited thereto. Inanother exemplary embodiment, at least one of the signal lines 121, 122,123, 124, and 171 and/or the initialization voltage line 134 may beshared by adjacent pixels.

The TFTs may include a driving TFT T1, a switching TFT T2, acompensation TFT T3, a first initialization TFT T4, an operation controlTFT T5, an emission control TFT T6, and a second initialization TFT T7.

The signal lines include the scan line 121 transferring a scan signal Snto the switching TFT T2 and the compensation TFT T3, the previous scanline 122 and the next scan line 124 respectively transferring a previousscan signal Sn−1 and a next scan signal Sn+1 to the first initializationTFT T4 and the second initialization TFT T7, the emission control line123 transferring an emission control signal En to the operation controlTFT T5 and the emission control TFT T6, and the data line 171 crossingthe scan line 121 and transferring a data signal Dm. The driving voltageline 172 transfers a driving voltage ELVDD to the driving TFT T1, andthe initialization voltage line 134 transfers an initialization voltageVINT which initializes the driving TFT T1 and a pixel electrode.

A driving gate electrode G1 of the driving TFT T1 is connected to afirst storage capacitor plate C1 of the storage capacitor Cst, a drivingsource electrode S1 of the driving TFT T1 is connected to the drivingvoltage line 172 via the operation control TFT T5, and a driving drainelectrode D1 of the driving TFT T1 is electrically connected to thepixel electrode of the OLED via an emission control TFT T6. The drivingTFT T1 receives a data signal Dm and supplies a driving current I_(OLED)to the OLED in response to a switching operation of the switching TFTT2.

A switching gate electrode G2 of the switching TFT T2 is connected tothe scan line 121, a switching source electrode S2 of the switching TFTT2 is connected to a data line 171, and a switching drain electrode D2of the switching TFT T2 is connected to the driving source electrode S1of the driving TFT T1 and simultaneously connected to the drivingvoltage line 172 via the operation control TFT T5. The switching TFT T2is turned on and performs a switching operation of transferring a datasignal Dm received via the data line 171 to the driving source electrodeS1 of the driving TFT T1 in response to a scan signal Sn received viathe scan line 121.

A compensation gate electrode G3 of the compensation TFT T3 is connectedto the scan line 121, a compensation source electrode S3 of thecompensation TFT T3 is connected to the driving drain electrode D1 ofthe driving TFT T1 and simultaneously connected to the pixel electrodeof the OLED via the emission control TFT T6, and a compensation drainelectrode D3 of the compensation TFT T3 is simultaneously connected tothe first storage capacitor plate C1 of the first storage capacitor Cst,a first initialization drain electrode D4 of the first initializationTFT T4, and the driving gate electrode G1 of the driving TFT T1. Thecompensation TFT T3 is turned on and diode-connects the driving TFT T1by electrically connecting the driving gate electrode G1 to the drivingdrain electrode D1 of the driving TFT T1 in response to a scan signal Snreceived via the scan line 121.

A first initialization gate electrode G4 of the first initialization TFTT4 is connected to the previous scan line 122, a first initializationsource electrode S4 of the first initialization TFT T4 is connected to asecond initialization drain electrode D7 of the second initializationTFT T7 and the initialization voltage line 134, and the firstinitialization drain electrode D4 of the first initialization TFT T4 isconnected to the first storage capacitor plate C1 of the storagecapacitor Cst, the compensation drain electrode D3 of the compensationTFT T3, and the driving gate electrode G1 of the driving TFT T1. Thefirst initialization TFT T4 is turned on and performs an initializationoperation of initializing the voltage of the driving gate electrode G1of the driving TFT T1 by transferring the initialization voltage VINT tothe driving gate electrode G1 of the driving TFT T1 in response to aprevious scan signal Sn−1 received via the previous scan line 122.

The operation control gate electrode G5 of the operation control TFT T5is connected to the emission control line 123, an operation controlsource electrode S5 of the operation control TFT T5 is connected to thedriving voltage line 172, and an operation control drain electrode D5 ofthe operation control TFT T5 is connected to the driving sourceelectrode S1 of the driving TFT T1 and the switching drain electrode D2of the switching TFT T2.

An emission control gate electrode G6 of the emission control TFT T6 isconnected to the emission control line 123, an emission control sourceelectrode S6 of the emission control TFT T6 is connected to the drivingdrain electrode D1 of the driving TFT T1 and the compensation sourceelectrode S3 of the compensation TFT T3, and an emission control drainelectrode D6 of the emission control TFT T6 is electrically connected tothe second initialization source electrode S7 of the secondinitialization TFT T7 and the pixel electrode of the OLED.

The operation control TFT T5 and the emission control TFT T6 aresimultaneously turned on in response to an emission control signal Enreceived via the emission control line 123, and the driving voltageELVDD is transferred to the OLED so that the driving current I_(OLED)flows through the OLED.

A second initialization gate electrode G7 of the second initializationTFT T7 is connected to the next scan line 124, a second initializationsource electrode S7 of the second initialization TFT T7 is connected tothe emission control drain electrode D6 of the emission control TFT T6and the pixel electrode of the OLED, and a second initialization drainelectrode D7 of the second initialization TFT T7 is connected to thefirst initialization source electrode S4 of the first initialization TFTT4 and the initialization voltage line 134. The second initializationTFT T7 is turned on and initializes the pixel electrode of the OLED inresponse to a next scan signal Sn+1 received via the next scan line 124.

Although FIG. 2 illustrates that the first initialization TFT T4 and thesecond initialization TFT T7 are respectively connected to the previousscan line 122 and the next scan line 124, the invention is not limitedthereto. In another exemplary embodiment, both the first initializationTFT T4 and the second initialization TFT T7 may be connected to theprevious scan line 122.

A second storage capacitor plate C2 of the storage capacitor Cst isconnected to the driving voltage line 172, and an opposite electrode ofthe OLED is connected to a common voltage ELVSS. Therefore, the OLED maydisplay an image by receiving the driving current I_(OLED) from thedriving TFT T1 and emitting light.

Although FIG. 2 illustrates that the compensation TFT T3 and the firstinitialization TFT T4 have dual gate electrodes, the invention is notlimited thereto. In an exemplary embodiment, the compensation TFT T3 andthe first initialization TFT T4 may have one gate electrode, forexample. Also, at least one of the TFTs T1, T2, T5, T6, and T7 inaddition to the compensation TFT T3 and the first initialization TFT T4may have dual gate electrodes. Various modifications may be madethereto.

An operation of each pixel PX according to an exemplary embodiment isdescribed below.

During an initialization period, when a previous scan signal Sn−1 issupplied via the previous scan line 122, the first initialization TFT T4is turned on in response to the previous scan signal Sn−1, and thedriving TFT T1 is initialized by the initialization voltage VINTsupplied via the initialization voltage line 124.

During a data programming period, when a scan signal Sn is supplied viathe scan line 121, the switching TFT T2 and the compensation TFT T3 areturned on in response to the scan signal Sn. In this case, the drivingTFT T1 is diode-connected and forward-biased by the compensation TFT T3which has been turned on.

Then, a compensation voltage Dm+Vth (Vth has a (−) value), which hasbeen reduced by a threshold voltage Vth of the driving TFT T1 from adata signal Dm supplied via the data line 171, is applied to the drivinggate electrode of the driving TFT T1. The driving voltage ELVDD and thecompensation voltage Dm+Vth are applied to both ends of the storagecapacitor Cst, and a charge corresponding to a voltage differencebetween both ends is stored in the storage capacitor Cst.

During an emission period, the operation control TFT T5 and the emissioncontrol TFT T6 are turned on in response to an emission control signalEn supplied via the emission control line 123. The driving currentI_(OLED) corresponding to a voltage difference between a voltage of thegate electrode G1 of the driving TFT T1 and the driving voltage ELVDDoccurs, and the driving current I_(OLED) is supplied to the OLED via theemission control TFT T6.

Hereinafter, the structure of the pixel illustrated in FIG. 2 isdescribed with reference to FIGS. 3 to 9.

FIG. 3 is a plan view of locations of a plurality of TFTs, a storagecapacitor, and a pixel electrode of the pixel PX of FIG. 2, FIGS. 4 to 8are plan views illustrating elements such as the plurality of TFTs, thestorage capacitor, and the pixel electrode of FIG. 3 on a layer basis,and FIG. 9 is a cross-sectional view of the plurality of TFTs, thestorage capacitor, and the pixel electrode taken along line IX-IX ofFIG. 3.

FIGS. 4 to 8 illustrate the arrangements of a wiring, an electrode, anda semiconductor layer with each of FIGS. 4 to 8 showing one layer, andan insulating layer may be between the layers illustrated in FIGS. 4 to8. In an exemplary embodiment, a first gate insulating layer 141 (referto FIG. 9) is between the layer illustrated in FIG. 4 and the layerillustrated in FIG. 5, a second gate insulating layer 143 (refer to FIG.9) is between the layer illustrated in FIG. 5 and the layer illustratedin FIG. 6, an interlayer insulating layer 150 (refer to FIG. 9) isbetween the layer illustrated in FIG. 6 and the layer illustrated inFIG. 7, and a planarization insulating layer 160 (refer to FIG. 9) isbetween the layer illustrated in FIG. 7 and the layer illustrated inFIG. 8, for example. The layers illustrated in FIGS. 4 to 8 may beelectrically connected to each other via a contact hole defined in atleast one of the above-mentioned insulating layers.

Referring to FIG. 3, a pixel PX includes the scan line 121, the previousscan line 122, the emission control line 123, the next scan line 124,and the initialization voltage line 134, each extending in a firstdirection (e.g., an x-direction) and respectively applying a scan signalSn, a previous scan signal Sn−1, an emission control signal En, a nextscan signal Sn+1, and the initialization voltage VINT (refer to FIG. 2).Also, the pixel PX may include the data line 171 and the driving voltageline 172 respectively applying a data signal Dm (refer to FIG. 2) andthe driving voltage ELVDD (refer to FIG. 2) and extending in a seconddirection (a y-direction) crossing the scan line 121, the previous scanline 122, the emission control line 123, the next scan line 124, and theinitialization voltage line 134. Also, the pixel PX includes the TFTs T1to T7, the storage capacitor Cst, and the OLED (refer to FIG. 2)electrically connected to the TFTs T1 to T7, the storage capacitor Cst.The pixel PX includes a shielding portion 106 preventing or reducingparasitic capacitance between the data line 171 and a node connectionline 174 connecting the driving TFT T1 to the compensation TFT T3.

The shielding portion 106 is between the data line 171 and the nodeconnection line 174 and may reduce crosstalk by reducing occurrence ofthe parasitic capacitance therebetween. The shielding portion 106 mayinclude a shielding semiconductor layer 126 and a metallic shieldinglayer 186 overlapping the shielding semiconductor layer 126. A constantvoltage is applied to the shielding portion 106. In an exemplaryembodiment, the shielding portion 106 is connected to the initializationvoltage line 134, and the initialization voltage of about −3.5 volts (V)may be applied to the shielding portion 106, for example.

Hereinafter, for convenience, a description is provided according to astacking order.

Referring to FIGS. 3, 4, and 9, semiconductor layers 130 a to 130 grespectively of the driving TFT T1, the switching TFT T2, thecompensation TFT T3, the first initialization TFT T4, the operationcontrol TFT T5, the emission control TFT T6, and the secondinitialization TFT T7 are in the same layer and include a same material.

The semiconductor layers 130 a to 130 g may be disposed over a bufferlayer 111 on the substrate 110. In an exemplary embodiment, thesubstrate 110 may include a glass material, a metallic material, or aplastic material such as polyethylene terephthalate (“PET”),polyethylene naphthalate (“PEN”), or polyimide. In an exemplaryembodiment, the buffer layer 111 may include an oxide layer such as SiOxand/or a nitride layer such as SiNx.

The driving semiconductor layer 130 a of the driving TFT T1, theswitching semiconductor layer 130 b of the switching TFT T2, thecompensation semiconductor layer 130 c of the compensation TFT T3, thefirst initialization semiconductor layer 130 d of the firstinitialization TFT T4, the operation control semiconductor layer 130 eof the operation control TFT T5, the emission control semiconductorlayer 130 f of the emission control TFT T6, and the secondinitialization semiconductor layer 130 g of the second initializationTFT T7 may be connected to each other and curved in various shapes.

The shielding semiconductor layer 126 may be between the data line 171and the node connection line 174 and be arranged in the seconddirection. The shielding semiconductor layer 126 may include first andsecond shielding regions 126 a and 126 b arranged in the seconddirection and spaced apart from each other with the previous scan line122 therebetween.

The first shielding region 126 a may be connected to the first andsecond initialization semiconductor layers 130 d and 130 g, and thesecond shielding region 126 b may extend between the switchingsemiconductor layer 130 b and the compensation semiconductor layer 130 cwhile spaced apart from the first shielding region 126 a. Although theillustrated exemplary embodiment illustrates that the first shieldingregion 126 a of the shielding semiconductor layer 126 is connected tothe first and second initialization semiconductor layers 130 d and 130g, the invention is not limited thereto. In another embodiment, theshielding semiconductor layer 126 may be an island type semiconductorlayer not connected to the first and second initialization semiconductorlayers 130 d and 130 g.

The shielding semiconductor layer 126 may be in a same layer as that inwhich the semiconductor layers 130 a to 130 g are arranged. In anexemplary embodiment, the shielding semiconductor layer 126 and thesemiconductor layers 130 a to 130 g may include polycrystalline silicon.In alternative exemplary embodiment, the shielding semiconductor layer126 and the semiconductor layers 130 a to 130 g may include amorphoussilicon or an oxide semiconductor such as a G-I-Z-O layer([(In₂O₃)_(a)(Ga₂O₃)_(b)(ZnO)_(c) layer](where each of a, b, and c are areal number satisfying a≧0, b≧0, and c≧0)). Hereinafter, for convenienceof description, a case where the shielding semiconductor layer 126 andthe semiconductor layers 130 a to 130 g include polycrystalline siliconis described.

The semiconductor layers 130 a to 130 g may include a channel region,and a source region may be at one side of the channel region and a drainregion may be at another side of the channel region. In an exemplaryembodiment, the semiconductor layers 130 a to 130 g may be doped withimpurities by the scan line 121, the previous scan line 122, theemission control line 123, the next scan line 124, and the firstelectrode layer 125 a, which will be described with reference to FIG. 5,as self-align masks, for example. Therefore, a source region and a drainregion not overlapping the scan line 121, the previous scan line 122,the emission control line 123, the next scan line 124, and the firstelectrode layer 125 a may include N-type or P-type impurities. While thesource region and the drain region are doped with impurities, theshielding semiconductor layer 126 may be also doped with the sameimpurities as the impurities of the source and drain regions. The sourceand drain regions of the semiconductor layers 130 a to 130 grespectively correspond to source and drain electrodes. Hereinafter, theterms of a source region and a drain region are used instead of a sourceelectrode and a drain electrode.

The driving semiconductor layer 130 a includes a driving channel region131 a, and a driving source region 176 a is disposed at one side of thedriving channel region 131 a and a driving drain region 177 a isdisposed at another side of the driving channel region 131 a. Thedriving channel region 131 a may be longer than channel regions 131 b to131 g. In an exemplary embodiment, the driving semiconductor layer 130 ahas a shape curved by a plurality of number of times, such as an omegaor a letter “S” shape, and thus may provide a long channel length insidea narrow space, for example. Since the driving channel region 131 a hasa long length, the driving range of a gate voltage applied to the firstelectrode layer 125 a, which is a driving gate electrode, widens, andthus a gray scale of light emitted from the OLED may be more finelycontrolled and a display quality may improve.

The switching semiconductor layer 130 b includes a switching channelregion 131 b, and a switching source region 176 b is disposed at oneside of the switching channel region 131 b and a switching drain region177 b at another side of the switching channel region 131 b. Theswitching drain region 177 b is connected to the driving source region176 a.

The compensation semiconductor layer 130 c includes compensation channelregions 131 c 1 and 131 c 3, and a compensation source region 176 c isdisposed at a side of the compensation channel region 131 c 1 and acompensation drain region 177 c at a side of the compensation channelregion 131 c 3. Compensation TFTs T3 in the compensation semiconductorlayer 130 c are dual TFTs and include the two compensation channelregions 131 c 1 and 131 c 3. A region 131 c 2 between the compensationchannel regions 131 c 1 and 131 c 3 is a region doped with impuritiesand, locally, serves as a source region of one of the dual TFTs andsimultaneously serves as a drain region of the other.

The first initialization semiconductor layer 130 d includes firstinitialization channel regions 131 d 1 and 131 d 3, and a firstinitialization source region 176 d is disposed at a side of the firstinitialization channel region 131 d 1 and a first initialization drainregion 177 d is disposed at a side of the first initialization channelregion 131 d 3. First initialization TFTs T4 in the first initializationsemiconductor layer 130 d are dual TFTs and include the two firstinitialization channel regions 131 d 1 and 131 d 3. A region 131 d 2between the first initialization channel regions 131 d 1 and 131 d 3 isa region doped with impurities and, locally, serves as a source regionof one of the dual TFTs and simultaneously serves as a drain region ofthe other.

The operation control semiconductor layer 130 e includes an operationcontrol channel region 131 e, and an operation control source region 176e is disposed at one side of the operation control channel region 131 eand an operation control drain region 177 e is disposed at another sideof the operation control channel region 131 e. The operation controldrain region 177 e may be connected to the driving source region 176 a.

The emission control semiconductor layer 130 f includes an emissioncontrol channel region 131 f, and an emission control source region 176f is disposed at one side of the emission control channel region 131 fand an emission control drain region 177 f at another side of theemission control channel region 131 f. The emission control sourceregion 176 f may be connected to the driving drain region 177 a.

The second initialization semiconductor layer 130 g includes a secondinitialization channel region 131 g, and a second initialization sourceregion 176 g is disposed at one side of the second initializationchannel region 131 g and a second initialization drain region 177 g atanother side of the second initialization channel region 131 g.

The first gate insulating layer 141 is disposed over the semiconductorlayers 130 a to 130 g. The first gate insulating layer 141 may includean inorganic material including an oxide or a nitride. In an exemplaryembodiment, the first gate insulating layer 141 may include SiO₂, SiNx,SiON, Al₂O₃, TiO₂, Ta₂O₅, HfO₂, or ZnO₂, for example.

Referring to FIGS. 3, 5, and 9, the scan line 121, the previous scanline 122, the emission control line 123, the next scan line 124, and thefirst electrode layer 125 a are disposed over the first gate insulatinglayer 141. The scan line 121, the previous scan line 122, the emissioncontrol line 123, and the first electrode layer 125 a include the samematerial. In an exemplary embodiment, the scan line 121, the previousscan line 122, the emission control line 123, and the first electrodelayer 125 a may include a single layer or a multi-layer including Mo,Al, Cu, Ti, etc., for example.

A portion or protruding portion of each of the scan line 121, theprevious scan line 122, the emission control line 123, the next scanline 124, and the first electrode layer 125 a corresponds to the gateelectrode of the TFTs T1 to T7.

Regions of the scan line 121 overlapping the switching channel region131 b and the compensation channel regions 131 c 1 and 131 c 3respectively correspond to a switching gate electrode 125 b andcompensation gate electrodes 125 c 1 and 125 c 2. Regions of theprevious scan line 122 overlapping the first initialization channelregions 131 d 1 and 131 d 3 respectively correspond to firstinitialization gate electrodes 125 d 1 and 125 d 2 providing the firstinitialization gate electrodes 125 d. Regions of the emission controlline 123 overlapping the operation control channel region 131 e and theemission control channel region 125 f respectively correspond to anoperation control gate electrode 125 e and an emission control gateelectrode 125 f. Regions of the next scan line 124 overlapping thesecond initialization channel region 131 g corresponds to a secondinitialization gate electrode 125 g.

Compensation gate electrodes 125 c are dual gate electrodes includingthe first and second compensation gate electrodes 125 c 1 and 125 c 2and may prevent or reduce occurrence of a leakage current.

A portion of the first electrode layer 125 a overlapping the drivingchannel region 131 a corresponds to the driving gate electrode G1. Thefirst electrode layer 125 a serves as the driving gate electrode G1 andsimultaneously serves as the first storage capacitor plate C1 of thestorage capacitor Cst. That is, the driving gate electrode G1 and thefirst storage capacitor plate C1 may be understood to be one body.

The second gate insulating layer 143 is disposed over the scan line 121,the previous scan line 122, the emission control line 123, the next scanline 124, and the first electrode layer 125 a. The second gateinsulating layer 143 may include an inorganic material including anoxide or a nitride. In an exemplary embodiment, the second gateinsulating layer 143 may include SiO₂, SiNx, SiON, Al₂O₃, TiO₂, Ta₂O₅,HfO₂, or ZnO₂, for example.

Referring to FIGS. 3, 6, and 9, the initialization voltage line 134 anda second electrode layer 127 are disposed over the second gateinsulating layer 143. The initialization voltage line 134 and the secondelectrode layer 127 include a same material. In an exemplary embodiment,the initialization voltage line 134 and the second electrode layer 127may include a single layer or a multi-layer including Mo, Al, Cu, Ti,etc., for example.

The initialization voltage line 134 transfers the initialization voltageVINT (refer to FIG. 2) initializing the driving TFT T1 and a pixelelectrode 210. The initialization voltage line 134 is electricallyconnected to the first initialization source electrode 176 d and thesecond initialization drain electrode 177 g. In an exemplary embodiment,the initialization voltage line 134 may be electrically connected to thefirst initialization source electrode 176 d and the secondinitialization drain electrode 177 g via the metallic shielding layer186, for example.

The second electrode layer 127 overlaps the first electrode layer 125 awith the second gate insulating layer 143 therebetween. The secondelectrode layer 127 corresponds to the second storage capacitor plate C2(refer to FIG. 2) of the storage capacitor Cst. An opening 127 hexposing the first electrode layer 125 a may be defined in the secondelectrode layer 127. One end of the node connection line 174 isconnected to the first electrode layer 125 a via the opening 127 h.

An interlayer insulating layer 150 is disposed over the initializationvoltage line 134 and the second electrode layer 127. In an exemplaryembodiment, the interlayer insulating layer 150 may include SiO₂, SiNx,SiON, Al₂O₃, TiO₂, Ta₂O₅, HfO₂, or ZnO₂, for example.

Referring to FIGS. 3, 7, and 9, the data line 171, the driving voltageline 172, the node connection line 174, an intermediate connection line175, and the metallic shielding layer 186 are disposed over theinterlayer insulating layer 150. The data line 171, the driving voltageline 172, the node connection line 174, the intermediate connection line175, and the metallic shielding layer 186 are in a same layer andinclude a same material.

In an exemplary embodiment, the data line 171, the driving voltage line172, the node connection line 174, the intermediate connection line 175,and the metallic shielding layer 186 may include a single layer or amulti-layer including a conductive material including Mo, Al, Cu, Ti,etc., for example. In an exemplary embodiment, the data line 171, thedriving voltage line 172, the node connection line 174, the intermediateconnection line 175, and the metallic shielding layer 186 may include amulti-layered structure of Ti/Al/Ti, for example.

The data line 171 extends in the second direction and is connected tothe switching source region 176 b of the switching TFT T2 via a contacthole 151 passing through the interlayer insulating layer 150.

The driving voltage line 172 extends in the second direction and isconnected to the operation source region 176 e of the operation controlTFT T5 and the second electrode layer 127 via contact holes 152 and 153defined in the interlayer insulating layer 150.

The driving voltage line 172 covers at least a portion of thecompensation TFT T3 and may prevent or reduce occurrence of anoff-current caused by external light. In an exemplary embodiment, thedriving voltage line 172 may cover a region exposed between thecompensation gate electrodes 125 c 1 and 125 c 2, which are dual gateelectrodes, that is, a region 131 c 2 between the compensation channelregions 131 c 1 and 131 c 3. In an exemplary embodiment, the drivingvoltage line 172 may cover at least a portion of a region of thecompensation TFT T3 including the dual gate electrodes adjacent to thenode connection line 174, for example.

When the driving voltage line 172 does not cover the compensation TFTT3, an off-current caused by external light increases, and a leakagecurrent is introduced to the driving TFT T1 such that color deviationmay occur. However, according to an exemplary embodiment, since thedriving voltage line 172 covers at least a portion of the compensationTFT T3, color deviation by a leakage current may be prevented orreduced.

The node connection line 174 connects the first electrode layer 125 a tothe compensation drain region 177 c of the compensation TFT T3 viacontact holes 154 and 155. The island type first electrode layer 125 amay be electrically connected to the compensation TFT T3 by the nodeconnection line 174.

The intermediate connection layer 175 is connected to the emissioncontrol TFT T6 via a contact hole 156. In an exemplary embodiment, theintermediate connection line 175 may be connected to the emissioncontrol drain region 177 f of the emission control TFT T6, for example.

Via contact holes 158 and 159, the metallic shielding layer 186electrically connects the first and second shielding regions 126 a and126 b spaced apart from each other. Although the metallic shieldinglayer 186 may be connected to the initialization voltage line 134 via acontact hole 157, the invention is not limited thereto.

The planarization insulating layer 160 may be over the data line 171,the driving voltage line 172, the node connection line 174, theintermediate connection layer 175, and the metallic shielding layer 186.In an exemplary embodiment, the planarization insulating layer 160 mayinclude an organic material such as acryl, benzocyclobutene (“BCB”),polyimide, or hexamethyldisiloxane (“HMDSO”).

Referring to FIGS. 3, 8, and 9, the pixel electrode 210 may be on theplanarization insulating layer 160. The pixel electrode 210 is connectedto the intermediate connection layer 175 via a contact hole 165 definedin the planarization insulating layer 160. The pixel electrode 210 isconnected to the emission control drain region 177 f of the emissioncontrol TFT T6 by the intermediate connection layer 175.

The pixel electrode 210 may be a reflective electrode. In an exemplaryembodiment, the pixel electrode 210 may include a reflective layerincluding Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, or a combinationthereof, and a transparent or semi-transparent electrode layer over thereflective layer, for example. In an exemplary embodiment, thetransparent or semi-transparent electrode layer may include at least oneof indium tin oxide (“ITO”), indium zinc oxide (“IZO”), zinc oxide(“ZnO”), In₂O₃, indium gallium oxide (“IGO”), and aluminum zinc oxide(“AZO”), for example.

Though not shown, a pixel-defining layer exposing the pixel electrode210 is disposed over the pixel electrode 210, and an emission layer 220is on the pixel electrode 210 exposed by the pixel-defining layer. In anexemplary embodiment, the emission layer 220 may include an organicmaterial including a fluorescent or phosphorescent material emittingred, green, blue, or white light, for example. The emission layer 220may include a low molecular organic material or a polymer organicmaterial. A functional layer such as a hole transport layer (“HTL”), ahole injection layer (“HIL”), an electron transport layer (“ETL”), andan electron injection layer (“EIL”) may be selectively further arrangedover and below the emission layer 220.

An opposite electrode 230 may be a transparent electrode. In anexemplary embodiment, the opposite electrode 230 may be a transparent orsemi-transparent electrode and may include a thin metallic layer havinga small work function including Li, Ca, LiF/Ca, LiF/Al, Al, Ag, Mg, or acombination thereof, for example. In an exemplary embodiment, atransparent conductive oxide (“TCO”) such as ITO, IZO, ZnO, or In₂O₃ maybe further arranged over the thin metallic layer.

As illustrated in FIG. 3, in the case where the driving voltage line 172covers at least a portion of the compensation TFT T3, a predeterminedgap is provided between the data line 171 and the node connection line174 connected to the first electrode layer 125 a which is the drivinggate electrode G1 of the driving TFT T1. The shielding portion 106 is inthe gap between the data line 171 and the node connection line 174, mayblock parasitic capacitance generated between the data line 171 and thefirst electrode layer 125 a which is the driving gate electrode G1, by asignal change of the data line 171, and may prevent or reduce occurrenceof crosstalk resulting from the parasitic capacitance.

As illustrated in FIGS. 3 and 9, the shielding portion 106 may includethe shielding semiconductor layer 126 and the metallic shielding layer186. In this case, the first shielding region 126 a and the secondshielding region 126 b of the shielding semiconductor layer 126 may beelectrically connected to each other by the metallic shielding layer 186which is a conductive layer, and may be electrically connected to theinitialization voltage line 134. The shielding semiconductor layer 126and the metallic shielding layer 186 of the shielding portion 106 mayrespectively block parasitic capacitance in a horizontal direction andparasitic capacitance in a vertical direction between the data line 171,the node connection line 174, and the semiconductor layers 130 b and 130c connected thereto.

According to the exemplary embodiments illustrated in FIGS. 3 to 9,although the structure in which the shielding semiconductor layer 126 iselectrically connected to the initialization voltage line 134 by themetallic shielding layer 186 has been described, the invention is notlimited thereto. In another exemplary embodiment, the shieldingsemiconductor layer 126 (e.g. first shielding region 126 a) may bedirectly connected to the initialization voltage line 134 via contactholes passing through insulating layers between the initializationvoltage line 134 and the shielding semiconductor layer 126, that is, thefirst and second gate insulating layers 141 and 143.

FIGS. 10 to 14 are plan views of a structure of a pixel PX according toanother exemplary embodiment. Except for shielding portions 206, 306,406, 506, and 606, the structure of the pixel PX of FIGS. 10 to 14 issubstantially the same as that of the pixel PX described above withreference to FIG. 3, and thus differences therefrom are mainly describedbelow for convenience of description.

Referring to FIG. 10, the shielding portion 206 includes a shieldingsemiconductor layer 226. The shielding semiconductor layer 226 mayinclude a first shielding region 226 a and a second shielding region 226b spaced apart from each other in the second direction. The shieldingsemiconductor layer 226 may include the same material as that of theabove-described shielding semiconductor layer 126 (refer to FIG. 3).

The first shielding region 226 a may be connected to the initializationvoltage line 134 via a contact hole 147 and may be electricallyconnected to the second shielding region 226 b via a metallic shieldinglayer 286 which is a conductive layer.

Although FIGS. 3 and 10 illustrate the shielding semiconductor layers126 and 226 having a structure in which the first and second shieldingregions 126 a and 226 a, and the second shielding regions 126 b and 226b are spaced apart from each other with the previous scan line 122therebetween, the invention is not limited thereto.

Referring to FIG. 11, the shielding portion 306 includes a shieldingsemiconductor layer 326 and a metallic shielding layer 386. Theshielding semiconductor layer 326 may overlap and cross a portion of theprevious scan line 122 and extend in the second direction.

In the case where the shielding semiconductor layer 326 overlaps aportion of the previous scan line 122 as illustrated in FIG. 11, anunexpected TFT may be disposed in which the overlapping region of theshielding semiconductor layer 326 and the previous scan line 122 becomesa channel region during a process of doping the first initializationsemiconductor layer 130 d using the previous scan line 122 as a mask forproviding the first initialization source and drain regions 176 d and177 d. To prevent the aforementioned phenomenon, as described withreference to FIGS. 3 and 10, the shielding semiconductor layers 126 and226 including the first shielding regions 126 a and 226 a and the secondshielding regions 126 b and 226 b spaced apart from each other with theprevious scan line 122 therebetween may be disposed. However, in a casewhere an operation of the unexpected TFT is ignorable or, unlike FIG.11, the previous scan line 122 does not cross the shieldingsemiconductor layer 326, the shielding semiconductor layer 326 mayextend in the second direction as illustrated in FIG. 11.

Although FIG. 11 illustrates that the shielding portion 306 includes adouble layer including the shielding semiconductor layer 326 and themetallic shielding layer 386, the invention is not limited thereto.

Referring to FIG. 12, the shielding portion 406 may include a singlelayer including a shielding semiconductor layer 426. The shieldingsemiconductor layer 426 may be connected to the initialization voltageline 134 via the contact hole 147 defined in an insulating layer betweenthe shielding semiconductor layer 426 and the initialization voltageline 134 and may receive a constant voltage.

Although the above exemplary embodiments have described a case where theshielding portions 106, 206, 306, and 406 include a layer including asemiconductor material, the exemplary embodiments are not limitedthereto. In another exemplary embodiment, the shielding portions mayonly include a layer including a metallic material.

Referring to FIG. 13, the shielding portion 506 may include a singlemetallic shielding layer 586. The single metallic shielding layer 586may include the same material as that of the metallic shielding layer186 described above with reference to FIG. 3.

Referring to FIG. 14, the shielding portion 606 may include a doublelayer including a first metallic shielding layer 676 and a secondmetallic shielding layer 686. The first metallic shielding layer 676 maybe in the same layer in which the initialization voltage line 134 isarranged and may include the same material as that of the initializationvoltage line 134. In an exemplary embodiment, the first metallicshielding layer 676 may include a first shielding region 676 a partiallyprotruding from the initialization voltage line 134 and a secondshielding region 676 b spaced apart from the first shielding region 676a and extending in the second direction, for example.

The second metallic shielding layer 686 may be in the same layer inwhich the above-described metallic shielding layer 186 (refer to FIG. 3)is arranged, may include the same material as that of the metallicshielding layer 186, and may be connected to the first shielding region676 a and the second shielding region 676 b via contact holes 158′ and159′, respectively.

Hereinafter, Table 1 shows parasitic capacitance Cgk between the dataline 171 and the node connection line 174 connected to the gateelectrode layer 125 a of the driving TFT T1 by the shielding portionaccording to exemplary embodiments.

TABLE 1 Comparative Embodiment Embodiment Embodiment Embodiment example1 2 3 4 Cgk(×10⁻¹⁵F) 0.152 0.1243 0.1296 0.1487 0.1401

The comparative example represents a case where a shielding portion isnot provided between the data line 171 and the node connection line 174,the embodiment 1 represents a case where the shielding portion 106illustrated in FIG. 3 is provided, the embodiment 2 represents a casewhere the shielding portion 406 illustrated in FIG. 12 is provided, theembodiment 3 represents a case where the shielding portion 506illustrated in FIG. 13 is provided, and the embodiment 4 represents acase where the shielding portion 606 illustrated in FIG. 14 is provided.

Referring to Table 1, since the shielding portion is provided, parasiticcapacitance between the data line 171 and the node connection line 174is reduced, and particularly, in the case where the shielding portionincludes a layer including a semiconductor material (the embodiments 1and 2), the parasitic capacitance has been remarkably reduced. This isunderstood as resulting from an influence of the parasitic capacitancein a horizontal direction between the semiconductor layers 130 b and 130c respectively connected to the data line 171 and the node connectionline 174 being relatively greater than an influence of parasiticcapacitance in the horizontal direction between the data line 171 andthe node connection line 174 in the same layer. That is, since thecompensation semiconductor layer 130 c is directly connected to thedriving semiconductor layer 130 a of the driving TFT T1, the parasiticcapacitance in the horizontal direction between the semiconductor layers130 b and 130 c has a relatively great influence on an operation of thedriving TFT T1. Therefore, the shielding portion may include theshielding semiconductor layer for effectively preventing the parasiticcapacitance.

Though the invention has been described with reference to the exemplaryembodiments illustrated in the drawings, this is merely provided as anexample and it will be understood by those of ordinary skill in the artthat various changes in form and details and equivalents thereof may bemade therein without departing from the spirit and scope of theinvention as defined by the following claims.

What is claimed is:
 1. A display device comprising: a first scan lineextending in a first direction; a data line and a driving voltage lineeach extending in a second direction crossing the first direction; aswitching thin film transistor connected to the first scan line and thedata line; a driving thin film transistor connected to the switchingthin film transistor and comprising: a driving semiconductor layer; anda driving gate electrode; a storage capacitor connected to the drivingthin film transistor and comprising first and second storage capacitorplates; a node connection line connected to the driving gate electrodeand arranged between the data line and the driving voltage line; and ashielding portion arranged between the data line and the node connectionline.
 2. The display device of claim 1, further comprising acompensation thin film transistor comprising a compensationsemiconductor layer and a compensation gate electrode, wherein thecompensation thin film transistor turns on in response to a scan signalof the first scan line and diode-connects the driving thin filmtransistor.
 3. The display device of claim 2, wherein one side of thenode connection line is connected to the compensation semiconductorlayer.
 4. The display device of claim 2, wherein the driving voltageline covers at least a portion of the compensation thin film transistor.5. The display device of claim 1, wherein the shielding portion extendsin the second direction.
 6. The display device of claim 1, furthercomprising an initialization voltage line which provides aninitialization voltage, wherein the shielding portion is electricallyconnected to the initialization voltage line.
 7. The display device ofclaim 1, wherein the shielding portion comprises at least one of ashielding semiconductor layer comprising a same material as that of thedriving semiconductor layer, and a metallic shielding layer comprising ametallic material.
 8. The display device of claim 7, further comprisinga second scan line extending in the first direction and crossing theshielding portion.
 9. The display device of claim 8, wherein theshielding semiconductor layer comprising a first shielding region and asecond shielding region spaced apart from each other in the seconddirection with the second scan line therebetween.
 10. The display deviceof claim 9, wherein the first shielding region is electrically connectedto the second shielding region by a conductive layer.
 11. The displaydevice of claim 10, wherein the conductive layer is the metallicshielding layer.
 12. The display device of claim 7, wherein theshielding semiconductor layer comprises polycrystalline silicon.
 13. Thedisplay device of claim 7, wherein the metallic shielding layercomprises a same material as that of at least one of the data line, thenode connection line, and the second storage capacitor plate.
 14. Thedisplay device of claim 1, wherein the driving gate electrode and thefirst storage capacitor plate comprise a same material with each other.15. The display device of claim 1, further comprising an organiclight-emitting diode electrically connected to the driving thin filmtransistor.